1. Field of the Invention
This invention relates to a detergent composition, and, more particularly, to a detergent composition which remarkably alleviates irritation and damage to the hair and the skin. The composition has excellent foaming ability and detergency, and is easily rinsed out and at the same time provides an agreeable feel to the hands during use.
2. Description of the Background Art
Because of the increased awareness concerning safety of the human body in recent years, a number of attempts have been undertaken to achieve mildness to the skin in the manufacture of laundry detergents, dishwashing detergents, detergents for use with household products, as well as those for the hair and the body. An example of such attempts is to adjust the pH of detergent compositions to a weakly acidic range,
i e., pH 5-6, which is near the pH of the human skin, thereby obtaining mildness to the skin. Another example is the use of a low irritant detergent base as a major detergent component. Amino acid type or alkylphosphate type surface active agents are used as low irritant detergent bases for this purpose (Japanese Patent Publication Nos. 40125/1975, 426023/1976, 9033/1980, and 27319/1983).
Although these surface active agents are low irritant, they have drawbacks such as insufficient foaming ability and detergency, poor solubility, and the like when used alone. Sodium alkylbenzene sulfonates have conventionally been used as a detergent base for detergent compositions. Although they have excellent detergency, their strong defatting action is liable to cause skin roughening.
For these reasons, sodium alkylethoxy sulfates which are less irritant have currently been used as a detergent base for dishwashing detergent compositions. Their use in combination with tertiary amine oxides, higher fatty acid diethanolamides, etc., as auxiliary surface active agents, has promoted various performances, providing dishwashing detergent compositions with reduced irritation to the skin.
In spite of these efforts for producing detergent compositions which are less irritant and mild to the skin, the level of improvement hitherto achieved is not yet satisfactory.
Alkyl glycosides, which are saccharide-derived surface active agents, are low irritant, nonionic surface active agents. Even though nonionic in nature, alkyl glycosides not only produce stable foams by themselves but also are known to act as foam stabilizers for anionic surface active agents. Because of this, a great deal of attention has been given to alkyl glycosides in recent years. Japanese Patent Laid-open No. 104625/1983, for example, discloses a foaming surfactant composition comprising an anionic surface active agent and an alkyl glycoside. Japanese Patent Laid-open No. 74999/1987 describes a low irritant liquid detergent composition for dishwashing use having superior foaming capability and detergency which comprises an alkyl glycoside, an anionic surface active agent, and a fatty acid alkanolamide. Japanese Patent Laid-open No. 186429/1983 reports a foaming surfactant composition comprising an alkyl glycoside, an anionic surfactant, and a fatty acid alkanolamide or an amine oxide. Japanese Patent Laid-open No. 500725/1987 discloses a viscosity-increased liquid detergent composition comprising an alkyl monoglycoside and an anionic surfactant. Also, Japanese Patent Laid-open No. 197495/1987 describes a liquid detergent composition for clothing comprising a nonionic surfactant, an anionic surfactant, and an alkyl glycoside. These detergent compositions, although exhibiting performances better than conventional detergent compositions using polyoxyethylenealkyl ethers as a major component, are not yet satisfactory, especially in their rinse-out performance and in the feel which they impart to the hands during washing. These detergent compositions also have problems of deterioration in their colors and odors when they are stored for a prolonged period of time, resulting in damages to their qualities.
In view of this situation, the present inventors have conducted extensive studies to make the best use of the superior characteristics of alkyl glycosides. As a result, the present inventors found that a combined use of a surface active agent having a sulfate and/or sulfonate group and an amine oxide and ethoxylated nonionic surface active agent together with an alkyl glycoside compound lessened the irritation to the skin, promoted detergency and foaming ability, and, at the same time, brought about improved rinse-out performance and better feeling to the hands during washing. The inventors also found that the detergent compositions to which a terpene type hydrocarbon selected from mono-terpene and sesqui-terpene, and 3-isothiazolone and/or its derivative are incorporated in addition to the above components, exhibited remarkably reduced deterioration in their solution colors and odors during storage over a prolonged period of time. Such findings have led to the completion of the present invention.